Model Checking 2007 Exercises

1. Model Checking 2007Exercises Barbara Jobstmann

2. Today • General • Mocha • Examples

3. Contact • Email: barbara.jobstmann@epfl.ch • Office: BC 358 • Mailing list: modelchecking2007@listes.epfl.ch • For all participants • subscribe • http://mtc.epfl.ch/courses/ModelChecking-2007/

4. Homework • Theoretical: • Examples and proofs on paper • Practical • Using MOCHA • Schedule • Given out: Thursday afternoon • Handed in: Thursday morning (before the lecture) or send an email • Discussed: Friday afternoon (from 13:15 to 15:00)

5. MOCHA • “MOCHA is a growing interactive software environment for system specification and verification.” • Three universities: • University of California at Berkeley • University of Pennsylvania • State University of New York at Stony Brook • Versions: • cmocha, jmocha • We will use jmocha 2.0

6. MOCHA • Systems written in RML (finite-state subset) • Specifications as invariants • Provides • Simulator • Checkers (enumerative, symbolic)

7. MOCHA • Where to find MOCHA? • http://embedded.eecs.berkeley.edu/research/mocha/ • Information and Help • MOCHA manual • Collection of “Do’s and Don’ts” at homepage of the lecture

8. Examples • Tiny examples • Boat example • Lock example • Sunscreen example

9. Cabbage, Goat, Wolf

10. Lock Example int got_lock = 0; do{ 1 if (*) { 2 lock();} 3 got_lock = got_lock + 1; 4 if (got_lock != 0) { 5 unlock(); 6 got_lock = got_lock - 1;} 7 } while(*) void lock() { 11 assert(L = 0); 12 L = 1; } void unlock(){ 21 assert(L = 1); 22 L = 0; }

11. Buggy Sunscreen

12. Buggy Sunscreen ws Window doOpen buttondown doClose buttonup Control goup open Screen godown close ss